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Biomedical subjects

Y Ochi

Publications and source records attributed to Y Ochi.

At least 19 recordsLinked to original sources
PubMed1979

An attempt to analyze various thyroid stimulators by the receptor assay using hTSH radioimmunoassay.

In an attempt to analyze thyroid stimulators in serum we developed an assay procedure using hTSH radioimmunoassay (RIA) in combination with receptor competition. The principle of this method is the determination by RIA of hTSH displaced by other thyroid stimulators from a thyroidal receptor preparation which previously bound unlabelled hTSH. Practically 4 microunits of hTSH were bound with human or bovine receptor, and then hTSH displaced by addition of test serum (0.1 ml) or samples dissolved in serum (0.1 ml) was measured by RIA. This assay can determine the thyroid stimulators other than hTSH in serum that has the displacement activity of 0.5-4.0 microunits of hTSH in the useful range, such as mU/ml level of bovine TSH or rat TSH. Cholera toxin that has the thyroid stimulating activity like TSH also showed the displacement of the bound hTSH. This assay is not applicable for the human serum with more than 5 microunits/ml of TSH, because the assay value is over estimated by the free hTSH derived from the test serum. On the other hand, eighteen sera with high LATS activity and 42 sera with negative LATS activity from patients with untreated hyperthyroidism did not show any displacement. This might be due to the lower binding activity of LATS with hTSH receptor or the lower sensitivity of this assay method. Although it is difficult to use this assay clinically because of its low sensitivity, increased TSH in animal serum can be determined by this assay. The principle of this method may be also useful for examining the receptor binding of other peptide hormone that can be determined by an RIA method.

Animals↗
PubMed1979

Effect of prostaglandin E1 on renin and aldosterone in hypertensive patients.

The effect of prostaglandin E1 (PGE1) on plasma renin activity (PRA) and plasma aldosterone concentration (PAC) was studied in the hypertensive subjects treated with or without 75 mg indomethacin or 60 mg propranolol for a week. Subsequent to the treatment with indomethacin for a week, PRA and PAC levels were decreased as compared to the control, without changes in the blood pressure and heart rate. During the infusion of PGE1, the blood pressure was decreased and the pulse rate was increased. PRA and PAC levels were also elevated. These changes of parameters were not different between the control and the indomethacin-treated subjects. PRA and PAC were suppressed after the treatment with propranolol. With the infusion of PGE1, the level of PRA was not significantly elevated, while, PAC was significantly increased by the infusion of 100 ng/Kg/min of PGE1. During the infusion of PGE1, the blood pressure was decreased while the pulse rate was increased in the subjects treated with propranolol. However, the elevation of the pulse rate was less remarkable than the control. These data indicate that PGE1 have important roles in the regulation of the release of renin and aldosterone. These findings also suggest that PGE1 may act to stimulate the secretion of aldosterone in man.

Adult↗
PubMed1978

Demonstration of antibody for glutamic pyruvic transaminase (GPT) in chronic hepatic disorders.

The present paper describes the detection of an autoantibody for glutamic pyruvic transaminase (GPT) in sera of patients with chronic hepatic disorders. In 16 out of 500 patients, the existence of an antibody for pig GPT was demonstrated by the double antibody method, gel filtration and radioimmunoelectrophoresis. The antibody was demonstrated as an immunoglobulin G (IgG) with either polyclonal or monoclonal type (kappa or lambda). The binding portion of IgG with GPT was determined as the fragment Fab, but not Fc of IgG. Because the binding of 125I-pig GPT with the patient's antibody was displaced by human GPT, this antibody may have the characteristic of cross reacting with both pig and human GPT. Although the mechanism of production of the antibody for GPT and the pathological significance of the antibody in chronic hepatic disorders remained obscure, possible inhibition of GPT activity in serum is suggested in the presence of this antibody.

Alanine Transaminase↗
PubMed1978

Changes in the cyclic nucleotides of rat thyroid, pituitary and plasma caused by methylthiouracil treatment.

Changes in the content of cyclic nucleotides (cAMP and cGMP) and related enzyme activities were observed in the rat thyroid, pituitary and plasma during the prolonged increase of endogenous TSH produced by treatment with methylthiouracil (MTU). Experiments were performed after 4 weeks treatment with MTU. The wet weight and cAMP content per wet weight of the thyroid increased 3 and 1.4 times respectively, but cGMP showed a slight decrease. Pituitary weight increased 1.3 times, but cAMP and cGMP content did not change. The cAMP level in plasma also increased about 1.3 times, but cGMP did not increase. The cAMP-phosphodiesterase activity in the thyroid, pituitary and plasma was increased 1.9, 1.4 and 1.3 times respectively after MTU treatment, while cGMP-phosphodiesterase showed no significant change. ATPase activity in the thyroid and pituitary was also increased more than 1.5 times after MTU treatment, while 5'-nucleotidase activitity decreased remarkably. These data indicate that the metabolism of the cyclic nucleotide system in the thyroid is stimulated by TSH.

Adenosine Triphosphatases↗
PubMed1978

Changes in cyclic nucleotides of rat thyroid by chronic administration of LATS and TSH.

The effects of LATS and TSH on the cyclic nucleotide content and enzymatic activity in rat thyroid was observed during the continuous administration of LATS or TSH for 6 days. Serum T4 and T3 levels were increased significantly compared with the saline controls. The cyclic nucleotide (cAMP and cGMP) levels and enzyme activities per wet weight of tissue were determined. The thyroid weight in both the LATS and TSH groups increased approximately two-fold, but cAMP and cGMP content per wet weight did not significantly change. Neither cyclic nucleotide showed any significant change in plasma. The cAMP-PDE activity in the thyroid significantly increased in both the LATS and TSH groups, but the cGMP-PDE activity was unchanged. Neither was cyclic nucleotide-PDE activity changed in the plasma. The ATPase activity in the thyroid increased markedly in both the LATS and TSH groups, while 5'-nucleotidase activity did not change. These data suggest that LATS and TSH appear to have a stimulatory effect on the metabolism of cAMP, but do not affect the metabolism of cGMP.

Adenosine Triphosphatases↗
PubMed1977

Methods for separation of long-acting thyroid stimulator (LATS) from sera containing LATS and TSH.

Methods were devised for separation of long-acting thyroid-stimulator (LATS) from TSH in serum containing both thyroid stimulators by using Rivanol, concanavalin A (con A), or staphylococcal protein A. When 3-5 volumes of 0.5% Rivanol solution were mixed to serum containing TSH or LATS activity, LATS activity remained mainly with IgG in the supernatant fraction. On the contrary, TSH activity was precipitated. When 10 mg con A was added to 1 ml test serum, almost all TSH activity was precipitated, but LATS activity remained in the supernatant fraction, which consisted mainly of IgG and albumin. Almost all LATS activity and part of the TSH activity were precipitated by addition of more than 7.5% polyethylene glycol (PEG), which was therefore not useful for separation of the stimulators in serum. Affinity chromatography on staphylococcal protein A-Sepharose was also found to separate the two thyroid stimulators in serum. By this method LATS-immunoglobulin bound to the protein A column, but no binding of the biologic and immunologic activity of TSH was observed. The protein A method seems the most useful of these four methods for complete separation of both stimulators.

Bacterial Proteins↗
PubMed1977

Failure of the reaction of beta2-microglobulin with staphylococcal protein A.

Because beta2-microglobulin is structurally similar to IgG, the reaction of beta2-microglobulin with Staphylococcal Protein A, which is known to react with the Fc region of IgG, was examined. 125I-beta2-microglobulin did not bind to Protein A. This may due to the difference in the amino acid sequence between beta2-microglobulin and the Fc region of IgG.

Beta-Globulins↗
PubMed1977

Suppression of elevated serum TSH levels in hypothyroidism by fusaric acid.

The effect of Fusaric acid (FA), a specific inhibitor of dopamine beta-hydroxylase, on humna TSH and thyroid hormone concentration (T4 and T3) was evaluated. Healthy subjects showed no significant changes in serum T3,T4 and TSH concentrations following the administration of FA calcium salt (FA-Ca) or placebo. Similarly, administration of FA-Ca for 4 weeks to hypertensive patients failed to produce significant changes in the serum T4 or T3 Resin Sponge Uptake values, and in the TSH and T3 responses to TRH. In contrast, FA-Ca produced a significant reduction on the high basal serum TSH level in patients with primary hypothyroidism. The mean nadir was 25% and ranged from 6 to 61%. As in the case of L-Dopa, the effect of FA-Ca on serum TSH is most clearly demonstrated in patients with primary hypothyroidism. Alterations in brain amines may directly or indirectly suppress pituitary TSH secretion. The possibility of changes in the peripheral distribution or turnover rate of TSH has not been excluded.

Adult↗
PubMed1977

Effect of LATS, TSH and cholera toxin on the thyroid gland in nude mice.

Three thyroid stimulators; LATS, TSH, and cholera toxin, have been tested by bioassay using congenitally athymic homozygous mice (nu/nu), nude mice and control littermates (nu/+) possessing normal thymic function. nu/+ Animals showed a response to LATS similarly to normal white mice of the ddN strain. The assay response to LATS in nu/nu animals was about half that in normal mice. TSH also showed a less stimulating action in nude mice. Cholera toxin made a long acting response similarly to LATS. The response to cholera toxin in nude mice was about half that of normal control mice. The thyroid of nude mice has a receptor for LATS-immunoglobulin, TSH or cholera toxin, which is similar to that of normal mice.

Animals↗
PubMed1977

Distribution of LATS activity in immunoglobulin G subclass.

The immunological character of LATS was examined by affinity chromatography on Anti-IgG, Anti-Fab, Anti-Fc and Staphylococcal Protein A bound Sepharose. By affinity chromatography on Anti-IgG, Anti-Fab and Anti-Fc bound Sepharose, it is possible to separate LATS-immunoglobulin from LATS positive serum without loss of activity. Affinity chromatography on Protein A bound Sepharose is useful for obtaining further purified LATS-immunoglobulin. By this method, it is possible to separate IgG molecules of the subclasses IgG(1), IgG(2) and IgG(4) with high LATS activity. LATS activity was not found in the IgG(3) fraction. When IgG(1) fraction was purified from the fraction containing the 3 subclasses of IgG(1), IgG(2) and IgG(4), about 85% of total protein was found in IgG(1). However, specific activity per protein of LATS in IgG(1) fraction did not change remarkably. After papain hydrolysis the thyroid stimulating activity of LATS-immunoglobulin was located in Fab fraction of these 3 subclasses of IgG(1), IgG(2) and IgG(4), and especially in IgG(1). The Fab fraction presents a short acting type of thyroid stimulating activity. These data indicate that LATS activity is mainly distributed in the Fab fragment of IgG(1).

Chromatography, Affinity↗
PubMed1976

Immunological studies on LATS-immunogloblin by the reaction with staphylococcal protein A.

The reaction of LATS activity with Staphylococcal Protein A, a specific binding protein with the Fc part of human IgG(1), IgG(2) and Ig(4), was examined. When IgG(1), IgG(2) and Ig(4) subclasses were removed from LATS positive sera or LATS-IgG fractions by affinity chromatography on Protein A-Sepharose, LATS activity decreased. Almost all LATS activity was found in the fraction that reacted with Protein A. It is suggested that LATS has an expression of a very distinct immunoglobulin G structure, and that LATS activity is distributed mainly in the fraction containing IgG(1), Ig(2) and Ig(4) in LATS positive serum;

Bacterial Proteins↗
PubMed1976

Determination of triiodothyronine in red blood cells by radioimmunoassay.

This study was undertaken to determine T3 content in red cells by radioimmunoassay. T3 in red blood cells was solubilized fairly from the stroma by hemolysis and red-cell T3 content could be determined directly by radioimmunoassay of the lysate. After hemolysing red cells with an equal volume of distilled water, 0.4 ml of the hemolyzate was used for the assay. The red-cell T3 content was expressed as ng/ml of red-cell volume. The normal T3 range in red cells was 0.20-0.45 ng/ml, and the Mean+/-SD was 0.32+/-0.10 ng/ml. The limit of detectability was 0.2 ng/ml. In hyperthyroid patients, the red-cell T3 content was more than 0.50 ng/ml with a Mean +/-SD of 1.35+/-0.65 ng/ml. In hypothyroid patients, red cells contained less than 0.25 ng/ml of T3, and there was an overlap from 0.20 to 0.25 ng/ml in the content of red-cell T3 in hypothyroid and euthyroid subjects. The patients with T3 toxicosis showed a high or normal level of red-cell T3. A positive correlation was noted between the red-cell T3 content and the serum T3 level (r=0.66). The correlation between the red-cell T3 content and the free T4 index (expressed as T7) was also positive (r=0.67). From these experiments, it is suggested that the red-cell T3 is low in comparison with the serum T3 levels, and depends on two factors; serum T4 and serum T3 levels.

Binding, Competitive↗